Interpretive Summary: The brown marmorated stink bug is an invasive species native to Asia that has become a significant threat to tree fruit, small fruit, vegetables, grapes, ornamentals and row crops. Therefore, we developed a laboratory bioassay to provide information concerning the overall effectiveness of insecticides against this insect. Adult insects were exposed to dry insecticide residues for 4.5h. Following this exposure period, the condition of the bug was rated daily (alive, moribund, or dead) for seven days. We found that the most effective materials provided a high degree of immediate mortality and little recovery. These included dimethoate, malathion, bifenthrin, methidathion, endosulfan, methomyl, chlorpyrifos, acephate, fenpropathrin, and permethrin. On the other hand, we saw a high degree of recovery from some neonicotinoids and pyrethroids. This baseline knowledge will enable us to better predict insecticide efficacy against brown marmorated stink bug in the field and ultimately will assist with the construction of effective management programs.

Technical Abstract:
The efficacy of 37 insecticides against adult Halyomorpha halys (Stal) was established based on exposure to 18-h old dry insecticide residue in laboratory bioassays. Adult H. halys were exposed to an insecticide residue for 4.5 h and then monitored daily for survivorship over a 7-d period. The proportion of dead and moribund insects was used as an estimate of overall insecticide efficacy against H. halys immediately after the exposure period and over the 7-d trial. Among all materials evaluated, 14 insecticides exhibited increasing efficacy, in which the percentage of dead and moribund insects (used as a measure of insecticide efficacy) increased by more than 10 percent after 7 d. By contrast, insecticide efficacy values of eight insecticides declined by more than 10 percent (based on recovery of adults from a moribund state) over the 7-d period with most belonging to the pyrethroid class. In this study, the efficacy value of neonicotinoid acetamiprid showed the greatest decline from 93 percent to 10 percent over 7 d. A lethality index (scale of 0-100) was developed to compare insecticides based on quantifying the immediate and longer-term effects of insecticide exposure on H. halys. Among all materials evaluated, dimethoate, malathion, bifenthrin, methidathion, endosulfan, methomyl, chlorpyrifos, acephate, fenpropathrin, and permethrin yielded the highest values (greater than 75) because of a high degree of immediate mortality with very little recovery. Our results provide baseline information regarding potential of candidate insecticides against adult H. halys and highlight the need to consider longer-term effects in establishing overall efficacy ratings against this invasive species.